The present disclosure relates generally to integrated circuits and, more particularly, to a charge pump circuit with multiple stages operating at different threshold voltages.
The demand for evermore compact, portable, and low cost consumer electronic devices has driven electronics manufacturers to develop and manufacture integrated circuits (IC) that operate with low power supply voltages resulting in low power consumption. There may be components of the devices that require higher voltages than the low power supply voltage. For example, devices having nonvolatile memory components such as flash memory may require very high voltages to program and erase memory cells. Generally, charge pump circuits have been used to generate high voltages in circuits with only low power supply voltages available. However, as device features and geometries continue to shrink to sub-micron size, the power supply voltages are also reduced. This can adversely effect a charge pump efficiency of the charge pump circuit in generating the required high voltages.
Therefore, what is needed is a simple and cost-effective apparatus and method for increasing the charge pump efficiency in charge pump circuits.